Miami Masters - Serena Williams vs. Na Li (17:00 GMT)

Serena Williams takes on Na Li this afternoon in the quarter-finals of the 2013 Sony Open in Miami (17:00 GMT start).

Williams was involved in one of Monday’s most exciting fourth round matches at the 2013 Miami Masters, coming back from a set down to defeat Dominika Cibulkova.

A wayward first set from Serena, in which she hit two winners and made 18 unforced errors, put her on the brink of defeat. Cibulkova than raced to a 3-0 lead in the second set, making an upset seem very possible. It wasn’t to be though, as Serena snapped into 'beast mode', as some pundits call it.

The world No. 1 finally took control of the match in the second set, and dominated the third to claim a 2-6 6-4 6-2 success victory.

"Mentally I was just struggling," Serena said afterwards.

"I was playing a really good opponent and I was making so many unforced errors out there - I couldn't pull myself together. But the crowd was great. They started saying, 'Come on Serena,' and someone over there kept telling me to relax and I listened, and I also saw my dad on the sideline and he was sitting there looking so calm and relaxed. I took all of that energy from the crowd and my dad and I knew I could do better."

Li was involved in a seesaw battle against Garbine Muguruza in round four, letting big first set leads slip during regular games and the tie-breaker. She found some consistency in the second set to achieve a 7-6 6-2 win over the Spanish teenager.

The weight of expectation later today will be placed mostly upon Serena. She holds a 6-1 head-to-head record against the fifth seed, having won her last four matches against her in straight sets.

Serena vowed to produce a better performance than she did against Cibulkova, and she’ll know better than to underestimate a player of Li’s class and calibre. Li certainly has an outside chance here, but following a huge wake-up call for Serena an upset appears to be unlikely.